It can be a problem with active suspension control systems, particularly in off-road vehicles that they do not respond suitably when the vehicle is traversing a steep side slope. This is because, in conventional systems, the presence of a side slope cannot be detected and the system therefore responds to a side slope as if the vehicle were cornering. This can result in the consumption of a lot of power as the system tries to compensate for what can be the equivalent of severe vehicle roll but which can last for long periods of time. This is because the vehicle can continue to traverse the side slope for a considerable length of time whereas severe roll is generally only present for short periods.
It is known from EP 0 283 004 to provide a vehicle roll control system in which the roll control mechanism is modified in dependence on the speed of the vehicle. However, this system still does not address the problem of roll control on a side slope.